PCSK9 and cardiac hypertrophy: Heart weight (per tibia length) and cardiomyocyte cross-sectional area of CM-Pcsk9−/− mice were similar to those of CM-Pcsk9+/+ mice at 10 weeks, but greater in CM-Pcsk9−/− than CM-Pcsk9+/+ mice at 28 weeks (Figure 2B–D), indicating cardiac hypertrophy.